`amixer set Master toggle` mutes but doesn't unmute

What happens if you manipulate the controls from within alsamixer?

The same, I can mute Master but I can't effectively unmute it afterwards.

Example:
* <Sound is on>.
* Open alsamixer.
* Mute Master with "M".
* Note that Headphone and Speaker don't appear as muted, not even with refresh ("L").
* Quit alsamixer and open it again.
* Note that Headphone and Speaker do appear as muted.
=> I.e. first problem is that the Headphone and Speaker were muted without the user requesting it, and without alsamixer getting notified about it.

* Unmute Master, Headphone and Speaker with the arrow keys + "M".
=> Second problem is that while they appear to be unmuted within alsamixer, the sound applet still shows my soundcard as muted, and I can hear no sound.
* Try changing the volume with the up/down arrow keys.
=> Again, while that appears to have an effect in the alsamixer UI, no sound actually comes out of the speakers, changing the volume doesn't unmute the card.

To sum up, muting either ONE of (Master, Headphone, Speaker) "secretly" mutes the other 2 ones as well, and unmuting them from the alsamixer UI doesn't bring the sound back.

Running the following does bring the sound back though:
amixer set Master unmute
amixer set Headphone unmute
amixer set Speaker unmute

Status changed to 'Confirmed' because the bug affects multiple users.

The attachment "force pulseaudio server dont mute pcm playback switch since it won't unmute this switch" of this bug report has been identified as being a patch. The ubuntu-reviewers team has been subscribed to the bug report so that they can review the patch. In the event that this is in fact not a patch you can resolve this situation by removing the tag 'patch' from the bug report and editing the attachment so that it is not flagged as a patch. Additionally, if you are member of the ubuntu-reviewers team please also unsubscribe the team from this bug report.

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This bug is clearly still active, how to use the patch?

I have this very same bug. The only way to workaround it it's to use some sort of script instead of the direct toggle input.

Same problem here with Xubuntu 12.10. Interestingly issuing the command "amixer set Master 3+" does not unmute the sound, while playing with volume horizontal scroller does unmute.

Under pulseaudio systems, please use
pactl set-sink-mute @DEFAULT_SINK@ 0
instead of amixer.

 when your sound card have ”PCM Playback Switch” which is only defined in

http://cgit.freedesktop.org/pulseaudio/pulseaudio/tree/src/modules/alsa/mixer/paths/analog-output.conf.common

 it won‘t unmute because none of conf files contain anything to switch it to on

http://git.kernel.org/?p=linux/kernel/git/tiwai/sound.git;a=commitdiff;h=247d85ee068610c50d66ee0cd3130e02c69f5f2e;hp=ac2e87366c18d49c6dc12e89ae4f4512f126eeb4

not only AC97 codec has pcm playback switch, the headphone of many desktop with hda codec are shared with primary output

This appears to be a duplicate of Bug #878986 and a problem with pulse audio.
using pactl instead is a solution that worked for me.
As documented here.
http://askubuntu.com/questions/118675/mute-key-mutes-alsa-and-pulseaudio-but-unmutes-only-alsa

> This appears to be a duplicate of Bug #878986 and a problem with pulse audio.

Indeed, thanks, marking as such.